export const GPS = {
	PI : 3.14159265358979324,
	x_pi : 3.14159265358979324 * 3000.0 / 180.0,
	delta : function (lat, lon) {

		var a = 6378245.0; //  a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
		var ee = 0.00669342162296594323; //  ee: 椭球的偏心率。
		var dLat = this.transformLat(lon - 105.0, lat - 35.0);
		var dLon = this.transformLon(lon - 105.0, lat - 35.0);
		var radLat = lat / 180.0 * this.PI;
		var magic = Math.sin(radLat);
		magic = 1 - ee * magic * magic;
		var sqrtMagic = Math.sqrt(magic);
		dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * this.PI);
		dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * this.PI);
		return {'lat': dLat, 'lon': dLon};
	},

	//84 to 火星坐标系 (GCJ-02)
	gps84_To_Gcj02 : function ( wgsLat , wgsLon )
	{
		if (this.outOfChina(wgsLat, wgsLon))
			return {'lat': wgsLat, 'lon': wgsLon};

		var d = this.delta(wgsLat, wgsLon);
		return {lat : wgsLat + d.lat,lon : wgsLon + d.lon};
	},

	//火星坐标系 (GCJ-02) to 百度坐标系 (BD-09)
	gcj02_To_Bd09:function(lat, lng)
	{
		let x_pi = 3.14159265358979324 * 3000.0 / 180.0;
		let x = lng;
		let y = lat;
		let z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * x_pi);
		let theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * x_pi);
		let lngs = z * Math.cos(theta) + 0.0065;
		let lats = z * Math.sin(theta) + 0.006;
		return {lat: lats,lon: lngs};
	},
	//百度坐标系 (BD-09) to 火星坐标系 (GCJ-02)
	bd09_To_Gcj02:function (lat, lng)
	{
		let x_pi = 3.14159265358979324 * 3000.0 / 180.0;
		let x = lng - 0.0065;
		let y = lat - 0.006;
		let z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * x_pi);
		let theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * x_pi);
		let lngs = z * Math.cos(theta);
		let lats = z * Math.sin(theta);

		return {lat: lats,lon: lngs}
	},
	gcj02_to_gps84:function (lat, lng)
	{
		var lat = +lat;
		var lng = +lng;
		var ee = 0.00669342162296594323; //  ee: 椭球的偏心率。
		var a = 6378245.0; //  a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
		if (this.outOfChina(lat, lng)) {
			return [lng, lat]
		} else {
			var dlat = this.transformLat(lng - 105.0, lat - 35.0);
			var dlng = this.transformLon(lng - 105.0, lat - 35.0);
			var radlat = lat / 180.0 * this.PI;
			var magic = Math.sin(radlat);
			magic = 1 - ee * magic * magic;
			var sqrtmagic = Math.sqrt(magic);
			dlat = (dlat * 180.0) / ((a * (1 - ee)) / (magic * sqrtmagic) * this.PI);
			dlng = (dlng * 180.0) / (a / sqrtmagic * Math.cos(radlat) * this.PI);
			var mglat = lat + dlat;
			var mglng = lng + dlng;
			return [lng * 2 - mglng, lat * 2 - mglat]
		}
	},
	gps84_To_Bd09 : function ( wgsLat , wgsLon )
	{
		let point=this.gps84_To_Gcj02(wgsLat,wgsLon);
		return this.gcj02_To_Bd09(point.lat,point.lon);
	},

	bd09_To_Gps84 : function ( wgsLat , wgsLon )
	{
		let point=this.bd09_To_Gcj02(wgsLat,wgsLon);
		return this.gcj02_to_gps84(point.lat,point.lon);
	},

	outOfChina : function (lat, lon) {
		if (lon < 72.004 || lon > 137.8347)
			return true;
		if (lat < 0.8293 || lat > 55.8271)
			return true;
		return false;
	},
	transformLat : function (x, y) {
		var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
		ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0;
		ret += (20.0 * Math.sin(y * this.PI) + 40.0 * Math.sin(y / 3.0 * this.PI)) * 2.0 / 3.0;
		ret += (160.0 * Math.sin(y / 12.0 * this.PI) + 320 * Math.sin(y * this.PI / 30.0)) * 2.0 / 3.0;
		return ret;
	},
	transformLon : function (x, y) {
		var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
		ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0;
		ret += (20.0 * Math.sin(x * this.PI) + 40.0 * Math.sin(x / 3.0 * this.PI)) * 2.0 / 3.0;
		ret += (150.0 * Math.sin(x / 12.0 * this.PI) + 300.0 * Math.sin(x / 30.0 * this.PI)) * 2.0 / 3.0;
		return ret;
	}
};
